Fix calls to logger's log(string)

This is in preparation for Google's PII efforts that are planned later.

Google-Bug-Id: b/209582622
Change-Id: I400fd6247760c22f2fc1e6e8d8990074e8b4159d

src/main/java/com/googlesource/gerrit/plugins/reviewers/ReviewerSuggest.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewers/ReviewerSuggest.java b/src/main/java/com/googlesource/gerrit/plugins/reviewers/ReviewerSuggest.java
index d397579..06a365f 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewers/ReviewerSuggest.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewers/ReviewerSuggest.java
@@ -67,7 +67,7 @@
             .collect(toSet());
       }
     } catch (StorageException | QueryParseException x) {
-      logger.atSevere().withCause(x).log(x.getMessage());
+      logger.atSevere().withCause(x).log("%s", x.getMessage());
     }
     return ImmutableSet.of();
   }

src/main/java/com/googlesource/gerrit/plugins/reviewers/Reviewers.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/reviewers/Reviewers.java b/src/main/java/com/googlesource/gerrit/plugins/reviewers/Reviewers.java
index fb5855c..865c289 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/reviewers/Reviewers.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/reviewers/Reviewers.java
@@ -121,7 +121,7 @@
           "Could not add default reviewers for change %d of project %s, filter is invalid: %s",
           changeNumber, projectName.get(), e.getMessage());
     } catch (StorageException x) {
-      logger.atSevere().withCause(x).log(x.getMessage());
+      logger.atSevere().withCause(x).log("%s", x.getMessage());
     }
   }
 }